High head solids pumps

ABSTRACT

A multi-stage centrifugal pump capable of passing solids utilising pairs of radially arranged continuous unrestricted volute passages through the impeller such that one passage of each pair of passages communicates directly between the inlet eye of the impeller communicating with the inlet in the pump casing and a sub-chamber formed by the impeller and the pump casing, the other passage of each pair communicates directly between a second inlet eye in the impeller communicating with said subchamber and a second subchamber in the casing in communication with the pump outlet.

United States Patent [191 Fuller June 18, 1974 HIGH HEAD SOLIDS PUMPS [76] Inventor: Ronald George Fuller, PO. Box

337, Hudson, Quebec, Canada [22] Filed: Aug. 2, 1971 21 Appl. No.: 167,957

[30] Foreign Application Priority Data Aug. 12, 1970 Canada 90638 [52] US. Cl. 415/53, 415/97 [51] Int. Cl. F04d 29/26, F04d 17/08 [58] Field of Search 415/97, 98, 213, 100, 101,

[56] References Cited UNITED STATES PATENTS 2,272,469 2/1942 Lannert 415/213 FOREIGN PATENTS OR APPLICATIONS 121,248 4/l946 Australia 415/97 574,079 12/1945 Great Britain 415/213 505,866 8/1930 Germany 415/97 l,343,0l 1 10/1963 France 415/100 498,815 12/1954 Canada 4l5/2l3 Primary Examiner-Henry F. Raduazo ABSTRACT A multi-stage centrifugal pump capable of passing solids utilising pairs of radially arranged continuous unrestricted volute passages through the impeller such that one passage of each pair of passages communicates directly between the inlet eye of the impeller communicating with the inlet in the pump casing and a subchamber formed by the impeller and the pump casing, the other passage of each pair communicates directly between a second inlet eye in the impeller communicating with said subchamber and a second subchamber in the casing in communication with the pump outlet.

4 Claims, 2 Drawing Figures 1 HIGH HEAD soups PUMPS BACKGROUND OF THE INVENTION The limitations imposed upon the design of centrifugal pumps intended to handle high density suspensions and entrained solids is such that hydraulic efficiency is subordinated to practical requirements to an extent that the pressure head developed by such pumps is in general limited to that produced by a single stage and by other restrictions imposed upon the design by the nature of the required duty. Higher heads beyond the capacity of single pumps presently available necessitate the use of a plurality of pumps connected in series with resulting complexity of connecting piping, increase of losses, controls and capital costs, etc. of a type familar to anyone well versed in the art.

Clearly in all such cases, very considerable economies are obtained by reducing the number of pumps and pumping stations, both in the form of capital expenditure and operating and maintenance costs.

Accordingly it is an object of this present invention to greatly increase the head capability of a pump suitable for this duty and thereby reduce the number of pumps required for any given head condition together with the cost of all attendant civil and other works directly related to the number of pumps and pump houses used.

It is a further object of this invention to provide a multi stage capability in a pump suitable for handling entrained solids.

lt is a further object of the present invention to provide a pump suitable for this duty possessing much improved mechanical balance of the rotating parts.

It is a further object of this invention to provide a pump suitable for this duty with much improved hydraulic balance.

It is a further object of this invention to provide a pump with a reduced tip velocity for any given discharge head resulting in a reduction in wear rates.

It is a further object of this invention to provide a pump suitable for this duty but with a substantial reduction in the end thrust imposed upon the impeller in relation to the head generated by it.

It is a further object of the present invention to substantially reduce the pressure imposed upon the pump packing, or shaft seal, where such is used, in relation to the head generated across the pump, and thereby reduce the pressure required for sealing water.

In the drawings which illustrate embodiments of this invention FIG. 1 shows a vertical section through an end suction horizontal pump with shaft stuffing box, and FIG. 2 shows a half section through a vertical pump with double volute and no stuffing box or shaft seal.

For reasons of simplicity, single ported (single vane) impellors are indicated and no cutwater, volute or vortex is shown, it being understood that a plurality of passages may be used.

The pumps illustrated comprises a casing (l) embracing an impellor (2)axially mounted upon a drive shaft (3). The suction end of easing (l) is closed by a suction cover (4) pierced by a suction port (5) mating with a passage (6) penetrating the impellor (2).

The pump casing (l) with suction cover 4) forms an annular space surrounding the circumference of impellor (2), which space is divided into two separate volumes (7) and (8) by means of an internal flange or partition (9) formed in the bore of the casing by means of a diaphram with a running clearance to the impellor which is sealed by a wear-ring, labarynth, or other suitable means which will be apparent to one well versed in the art.

The impellor (2) is penetrated by two separate sets of passages, one of which (6) serves to connect the suction port (5) with the closed volume (7) and the other (10) connects the closed volume (7) with volume (8) which latter is preferably shaped in the form of a volute and communicates with a discharge outlet (11).

It will be apparent that rotation of impellor (2) at an appropriate speed will cause centrifugal force to act upon any fluid material entrained in passages (6) and (10), the passages following generally helical paths as dictated by hydraulic and centrifugal disciplines, said centrifugal forces will promote the flow of fluid from the suction port (5) through passage (6) to volume (7) and thence through passage (10) to volume (8) to discharge outlet (11) It will be seen that Passage (10) serves as a second stage to passage (6) and that the head imparted to the fluid in passage (10) is incremental to that imparted to the fluid when in passage (6) thereby doubling the head imparted by the single pass passages heretofor taught by the art for single impellor pumps, and securing the other advantages which are amongst the objects of this invention.

The invention further resides in the combination, construction, and arrangement of parts illustrated in the accompanying drawings, and whilst there are shown two variants for the purpose of simplicity, it is to be understood that the same is merely illustrative of the invention and the invention is capable of modification and change and comprehends other details of construction without departing from the spirit thereof, or scope of the appended claims.

What I claim is:

l. A centrifugal pump comprising a casing defining a chamber, an impeller rotationally mounted within the chamber, means including the impeller for dividing the chamber into two separate open and unobstructed subchambers, the casing including an inlet and a separate outlet, pumping passageways through the impeller grouped in pairs, one passageway of each pair of passageways providing direct communication between the inlet of the casing and one of said sub-chambers remote from the inlet, the other passageway of each air of passageways providing direct communication between said remote sub-chamber and the other sub-chamber, the two passageways of each pair of passageways in substantial hydraulic and mechanical balance with each other, both passageways of each pair of passageways communicating with said remote sub-chamber, said remote subchamber providing direct and unobstructed communication between said both passageways, said outlet of the casing communicating with said other sub-chamber.

2. A centrifugal pump as claimed in claim 1, wherein the inlet to the casing is concentric about the axis of rotation of the impeller within the casing, said one passageway having an inlet on one side of impeller concentric with the axis of rotation adjacent said inlet of the casing.

3. A centrifugal pump as claimed in claim 1, wherein the axis of one passageway of each pair of passageways is displaced radially around the circumference of the impeller by an interval of approximately from the impeller by an interval of approximately from the axis of the other passageway of said pair of passageways. 

1. A centrifugal pump comprising a casing defining a chamber, an impeller rotationally mounted within the chamber, means including the impeller for dividing the chamber into two separate open and unobstructed sub-chambers, the casing including an inlet and a separate outlet, pumping passageways through the impeller grouped in pairs, one passageway of each pair of passageways providing direct communication between the inlet of the casing and one of said sub-chambers remote from the inlet, the other passageway of each air of passageways providing direct communication between said remote sub-chamber and the other sub-chamber, the two passageways of each pair of passageways in substantial hydraulic and mechanical balance with each other, both passageways of each pair of passageways communicating with said remote sub-chamber, said remote subchamber providing direct and unobstructed communication between said both passageways, said outlet of the casing communicating with said other sub-chamber.
 2. A centrifugal pump as claimed in claim 1, wherein the inlet to the casing is concentric about the axis of rotation of the impeller within the casing, said one passageway having an inlet on one side of impeller concentric with the axis of rotation adjacent said inlet of the casing.
 3. A centrifugal pump as claimed in claim 1, wherein the axis of one passageway of each pair of passageways is displaced radially around the circumference of the impeller by an interval of approximately 180* from the axis of the other passageway of said pair of passageways.
 4. A centrifugal pump as claimed in claim 2, wherein the axis of one passageway of each pair of passageways is displaced radially around the circumference of the impeller by an interval of approximately 180* from the axis of the other passageway of said pair oF passageways. 